package features.advance.leetcode.array.easy;

import java.util.Arrays;

/**
 *  剑指 Offer 29. 顺时针打印矩阵
 *
 *  难度：简单
 *
 * 输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字。
 *
 *
 * 示例 1：
 *
 * 输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
 * 输出：[1,2,3,6,9,8,7,4,5]
 * 示例 2：
 *
 * 输入：matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
 * 输出：[1,2,3,4,8,12,11,10,9,5,6,7]
 *
 *
 * 限制：
 *
 * 0 <= matrix.length <= 100
 * 0 <= matrix[i].length <= 100
 * 注意：本题与主站 54 题相同：https://leetcode-cn.com/problems/spiral-matrix/
 *
 * @author LIN
 * @date 2021-06-07
 */
public class Offer29 {
    public static void main(String[] args) {

        int[][] matrix = {{1,2,3,4},{5,6,7,8},{9,10,11,12}};

        Solution solution = new Solution() {
            @Override
            public int[] spiralOrder(int[][] matrix) {
                if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
                    return new int[0];
                }
                int rows = matrix.length, columns = matrix[0].length;
                int[] order = new int[rows * columns];
                int index = 0;
                int left = 0, right = columns - 1, top = 0, bottom = rows - 1;
                while (left <= right && top <= bottom) {
                    for (int column = left; column <= right; column++) {
                        order[index++] = matrix[top][column];
                    }
                    for (int row = top + 1; row <= bottom; row++) {
                        order[index++] = matrix[row][right];
                    }
                    if (left < right && top < bottom) {
                        for (int column = right - 1; column > left; column--) {
                            order[index++] = matrix[bottom][column];
                        }
                        for (int row = bottom; row > top; row--) {
                            order[index++] = matrix[row][left];
                        }
                    }
                    left++;
                    right--;
                    top++;
                    bottom--;
                }
                return order;
            }
        };
        int[] res = solution.spiralOrder(matrix);
        System.out.println(Arrays.toString(res));
    }

    static class Solution {
        public int[] spiralOrder(int[][] matrix) {
            if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
                return new int[0];
            }
            int rows = matrix.length; // 行
            int columns = matrix[0].length; // 列
            boolean[][] visited = new boolean[rows][columns];
            int total = rows * columns;
            int[] order = new int[total];
            int row = 0, column = 0;
            int[][] directions = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
            int directionIndex = 0;
            for (int i = 0; i < total; i++) {
                order[i] = matrix[row][column];
                visited[row][column] = true;
                int nextRow = row + directions[directionIndex][0], nextColumn = column + directions[directionIndex][1];
                if (nextRow < 0 || nextRow >= rows || nextColumn < 0 || nextColumn >= columns || visited[nextRow][nextColumn]) {
                    directionIndex = (directionIndex + 1) % 4;
                }
                row += directions[directionIndex][0];
                column += directions[directionIndex][1];
            }
            return order;
        }
    }

}
